The invention relates to a process for electrostatically coating objects using a liquid, for instance liquid paint, by applying a high voltage to a spray bell and by feeding the fluid to the spray bell driven in revolving manner.
Methods and devices to electrostatically coat objects with paint are known in large numbers. Thus there are spray guns of the most diverse designs, wherein the paint means is sprayed by compressed air, or in airless manner. A needle-shaped high-voltage electrode is located at the spraying site, whereby, on account of the high concentration of field lines, an electrical charging of the spray mist takes place.
Moreover spraying systems are known, wherein the paint means is electrostatically removed as a thin film from a knife-edge. The feed of the paint means to the spray edge is implemented by gravity or centrifugal forces.
Lastly it is known that atomization is possible by high centrifugal forces, in the presence or absence of electric fields, where said atomization essentially comprises the advantages of the above cited methods. However this system suffers from the drawback that due to the design of the spray bell, even in the case of a central enamel supply, the paint means prior to atomization must pass sites of unstability (discontinuous changes in cross-section, jump in Coriolis acceleration), which entail changes in the paint means (for instance, entrainment of air). Moreover these systems require a central atomizing hub to feed the paint means to the spray edge. This atomizing hub is subjected to uncontrollable soiling.